Filter devices for holding of filter elements are readily available on the market in a plurality of versions. A significant portion of production costs in such filter devices is spent on the construction of the retaining device for detachable fixing of the filter element within the pertinent housing and of the sealing device for sealing the interior of the filter element relative to the filter housing.
In a filter device of this type as shown in document WO 2005/123216 A1, in an effort to keep production costs especially low, the sealing device is designed as a one-piece component of a pertinent end cap of the filter element; i.e., it is produced from the same material as the end cap. This construction makes production cheaper and easier. Conventional separate sealing devices extending between a filter element and a housing terminating part can then be omitted. In addition, mounting processes are simplified because there is no need to focus on handling separate sealing devices. On the other hand, limitations arise with respect to the quality of the seal formed because plastic materials which are conventional and suitable for production of the end caps cannot all be regarded as suitable sealing materials. This situation results in limitations in the choice of materials in the production of the end caps. In addition, for a sealing device molded in one piece on the end cap, a close tolerance is necessary in the production of the end caps to ensure a reliable seal.